Conventionally, it has been known that causes of an ischemic disease of internal organs are generally categorized as hematogenous disorder and dysfunction of the organ itself. For example, stenosis being an example of hematogenous disorder of a coronary artery is a serious lesion leading to the ischemic heart disease. With respect to the ischemic heart disease, it is required to judge whether to perform medication or stent therapy. In recent years, a method of measuring myocardial fractional flow reserve (FFR) by using a pressure wire has been recommended in a coronary angiography by a catheter as a diagnosis for performing hematogenous ischemia estimation of a coronary artery.
Meanwhile, there has been known a method of performing the hematogenous ischemia estimation of a coronary artery non-invasively by using medical images of a heart collected by a medical-diagnostic imaging apparatus such as an X-ray CT (Computed Tomography) apparatus, an MRI (Magnetic Resonance Imaging) apparatus, or an ultrasonic diagnostic apparatus. In recent years, the hematogenous ischemia estimation has been performed by such various methods, and medical treatment according to the estimation is performed.